A new study is throwing doubt on the common belief that
avian influenza outbreaks across the United States and Canada last year
originated with migrating waterfowl.
Researchers at St. Jude Children’s Research Hospital say
highly-pathogenic avian influenza strains were never detected in wild birds for
43 years and said they found none in 123,000 samples they collected before the
2015 outbreak.
In the United States, the government estimates 43 million farm
birds either died or were euthanized; in Canada flocks were sacrificed in the Fraser
Valley of British Columbia over the Christmas holidays before 2015 and there
were three flocks in Oxford County, Ont., that were infected.
“Although the stamping out strategies adopted by the poultry
industry and animal health authorities in Canada and the United States—which
included culling, quarantining, increased biosecurity, and abstention from
vaccine use—were successful in eradicating the HP H5Nx viruses from poultry,
these activities do not explain the apparent disappearance of these viruses
from migratory waterfowl,” the researchers stated in an abstract of their
findings.
The scientists believe that more research is needed to fully
understand HPAI resistance in wild waterfowl with the goal of improving the
industry’s knowledge of the mechanisms that prevent wild birds from
perpetuating spread of the virus.
